Problem: Tiffany ate 3 slices of cake. Christopher ate 4 slices. If there were 3 slices remaining, what fraction of the cake was eaten?
Solution: $\text{fraction of cake eaten} = \dfrac{\text{number of slices eaten}}{\text{number of slices total}}$ Since they ate 7 slices of cake with 3 slices remaining, they must have begun with 10 slices. They ate ${7}$ out of $10$ slices. They ate $\dfrac{7}{10}$ of the cake.